009
FXUS65 KBYZ 011853
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1253 PM MDT MON JUN 1 2026
KEY MESSAGES
- CHANCE OF SHOWERS AND THUNDERSTORMS TONIGHT THROUGH TUESDAY
NIGHT. A FEW THUNDERSTORMS COULD BECOME SEVERE, MAINLY OVER
EASTERN MONTANA.
- SHOWER AND THUNDERSTORM CHANCES RETURN THURSDAY. A FEW
THUNDERSTORMS COULD BECOME SEVERE, MAINLY OVER EASTERN MONTANA.
- NEAR NORMAL TEMPERATURES THROUGH THURSDAY BEFORE TEMPERATURES
TREND ABOVE AVERAGE LATE IN THE WEEK INTO THE WEEKEND.
DISCUSSION
NEXT 7 DAYS (THROUGH NEXT MONDAY)...
A 500 MB RIDGE OVER THE PLAINS AND A TROUGH OVER WESTERN AND
CENTRAL MONTANA IS CREATING A FAVORABLE ENVIRONMENT FOR
THUNDERSTORMS ACROSS MUCH OF THE NORTHERN PLAINS THROUGH TUESDAY.
THE 700 MB TROUGHING AND THERMAL RIDGE WILL COMBINE TO ADVECT GULF
MOISTURE INTO THE NORTHERN PLAINS LEADING TO DEWPOINTS IN THE 50S
F AND AN AXIS OF INSTABILITY (500-1,000 J/KG CAPE). STARTING THIS
AFTERNOON AND EVENING, THE UPPER LEVEL TROUGH WILL CREATE A
REGION OF >60 KTS OF 0-6 KM SHEAR COMBINED WITH A 25-30 KT LOW
LEVEL JET INCREASING LOW LEVEL HELICITY. THESE INGREDIENTS WILL BE
IN PLACE THIS EVENING AND OVERNIGHT FOR FAR SOUTHEAST MONTANA
(CARTER AND FALLON COUNTIES). 0-6 KM SHEAR IS EXPECTED TO BE
PERPENDICULAR TO FORCING LEADING TO A LIKELY ISOLATED DISCRETE
CONVECTION MODE WITH HAIL (>1 INCH) BEING THE BIGGEST THREAT.
BY TUESDAY, THE 500 MB TROUGH WILL HAVE MOVED SLIGHTLY TO THE
EAST PUSHING THE BEST 0-6 KM SHEAR INTO THE DAKOTAS. FORCING WILL
LIKELY BE STRONGER TUESDAY HOWEVER WITH CONVECTION DEVELOPING
ALONG A COLD FRONT IN AN ENVIRONMENT WITH ADEQUATE INSTABILITY
(~500 J/KG) AND SHEAR (40-50 KTS). PARALLEL ORIENTED SHEAR WILL
LEAD TO LINEAR CONVECTION BEING MORE LIKELY. CONVECTION TUESDAY IS
EXPECTED TO START IN THE WEST BEFORE THE RISK SHIFTS TO THE EAST
IN THE EVENING AND OVERNIGHT. THE HIGHEST RISK FOR SEVERE STORMS
WILL ONCE AGAIN BE IN SOUTHEAST MONTANA (CARTER, FALLON, POWDER
RIVER, AND CUSTER COUNTIES) WHERE HAIL IN EXCESS OF 1 INCH AND
WINDS IN EXCESS OF 60 MPH WILL BE THE MAIN THREATS.
ANOTHER WAVE MOVES ACROSS THE REGION THURSDAY BRINGING ADDITIONAL
SHOWER AND THUNDERSTORM CHANCES (50-70%). FAR SOUTHEASTERN
MONTANA HAS THE BEST CHANCE AT SEEING SEVERE THUNDERSTORMS
THURSDAY. TEMPERATURES INCREASE THROUGHOUT THE WEEK WITH 70S F
THROUGH THURSDAY INCREASING INTO THE 80S AND LOW 90S F FRIDAY
THROUGH THE WEEKEND. AN UPPER LEVEL TROUGH TO OUR WEST BRINGS
PRECIPITATION CHANCES (30-50%) FOR SUNDAY AND MONDAY. NOT MUCH
MORE IS KNOWN ABOUT THIS SYSTEM AT THIS TIME. TORGERSON
AVIATION
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND
MOVE NORTHEAST THROUGH THE AREA THIS AFTERNOON AND EVENING. ANY
SHOWER OR THUNDERSTORM THAT DOES DEVELOP COULD PRODUCE BRIEF
ERRATIC WIND GUSTS MAINLY IN THE 30S TO 40S KNOTS. OVER FAR SOUTH-
EASTERN MONTANA, A STRONG TO SEVERE THUNDERSTORM CAPABLE OF
PRODUCING HEAVY RAIN AND HAIL IS POSSIBLE AS WELL (MARGINAL RISK
FROM THE STORM PREDICTION CENTER, 1/5). DUE TO THE ISOLATED NATURE
OF STORMS TODAY, THE PROBABILITY FOR THUNDER AT A GIVEN TERMINAL
REMAINS LOW. STORM ACTIVITY WILL DIMINISH FROM WEST TO EAST
THROUGH 06Z TONIGHT. LA/PM
PRELIMINARY POINT TEMP/POPS
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 046/073 047/076 051/078 051/083 055/093 056/078 050/081
11/B 20/B 15/T 41/U 00/U 12/T 31/B
LVM 039/070 041/077 045/073 043/080 046/087 047/070 042/076
31/B 10/U 17/T 31/U 01/N 24/T 42/T
HDN 043/075 045/076 049/081 049/082 053/093 055/078 049/081
20/B 30/B 15/T 52/W 00/U 11/B 31/B
MLS 045/073 047/074 048/079 053/080 055/091 060/084 054/081
60/B 10/U 04/T 73/T 00/U 10/B 31/B
4BQ 047/075 048/074 049/079 052/080 053/091 059/084 053/080
40/U 61/B 14/T 62/W 00/U 11/B 31/B
BHK 046/074 045/072 044/077 051/077 052/086 058/084 053/078
92/B 41/B 13/T 74/T 10/N 11/N 31/B
SHR 041/075 043/074 045/077 046/079 048/091 051/079 046/079
10/U 31/B 15/T 31/U 10/U 01/U 42/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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